API dim to n_dim in make_sparse_spd_matrix

[adam2392]

Reference Issues/PRs

Fixes: #27669

What does this implement/fix? Explain your changes.

Deprecates dim in place of n_dim.

Any other comments?

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[glemaitre]

You need to add a specific test to check the deprecation warning.
You also need a new test for checking that we raise the expected error.

I also saw some other failure, I assume that we were using the dim variable in someway.

[glemaitre]

do not change n_dim but _n_dim. We should raise an error if a user try to specify both n_dim and dim.

I assume that the time of the deprecation, we need to have n_dim=None to detect explicitely if a user pass n_dim=1 or not. This is annoying but I don't see how to detect this case otherwise. This would not change the default value because None would default to 1. Somehow, we can omit to document it explicitely, and make a more silent deprecation because I don't think that any user will use n_dim=Noe explicitely to set it to 1.

[glemaitre]

LGTM on my side. Thanks @adam2392

[thomasjpfan]

Otherwise LGTM